Manhole extension



WW, 9 1% T. A. PELSUE EQWWW MANHOLE EXTENSION Filed March 30, 1964 2 Sheets-Sheet 1 F I G. 2. INVENTOR TH U R MAN A. PELS U E ATTORNEYS United States Patent M 3,294,000 MANHOJLE EXTENSIDN Thurman A. Pelisue, 3706 Hibiscus Way, Denver, Colo. 80237 Filed Mar. 30, 1964, Ser. No. 355,880 3 Claims. (Cl. 9438) This invention relates to manhole extensions and, more specifically, to an improved device of the type aforementioned that includes a simplified gasket and retaining structure therefor.

In nearly all metropolitan areas most gas and water lines, and many telephone and other electrical lines, are placed underground when they are protected from the weather. Vast networks of subsurface tunnels exist, therefore, into which access is had through vertical passages terminating on the surface in reinforced openings commonly referred to as manholes. These manholes comprise circular access openings defined by heavy metal rings fastened to the top of standpipes. The rings are mounted flush with the surrounding surface and generally flanged in some manner so as to become a more or less permanent fixture attached to the adjoining street, roadway or other surface covering.

In general, an annular groove is provided around the inside top surface of the ring that defines a shoulder adapted to support a heavy metal lid or so-called manhole cover.

The primary purpose of these manholes is, of course, to provide ready access to the underground facilities for purposes of maintenance and repair. In order to perform these service functions, the cover must be removed and remain off so that fresh air, heat, materials and tools can be made available to the workman underground through the medium of service trucks, blowers and heaters located on the surface.

Now, under unfavorable weather conditions such as rain and snow, melting snow and floods, these underground facilities can become most uncomfortable, and in some instances impossible, to work in unless some means is provided for preventing water from running down into the manhole. Also, if excessive amounts of water are allowed to enter these subsurface tunnels, serious damage can occur to the facilities contained therein, some of which are not designed to withstand such treatment which fact necessitates their being placed underground in the first place.

Obviously, the simplest and most practical way of preventing surface water from getting underground through the access opening provided by the manhole is to mount an upstanding extension on the ring that effectively raises the height of the standpipe several inches above the surrounding terrain. The prior art attempts to provide such an extension have, however, proven to be somewhat impractical for several reasons.

Perhaps the most significant shortcoming of the prior art extensions is their inability to provide a good watertight seal along the area where they join the ring. Obviously, if they leak at this point to any appreciable extent, their utility is lost.

Another significant problem is that of tolerances. The rings into which these extensions must fit and produce a substantially water-tight seal vary rather widely in diameter and are not always truly circular. In other words, these rings may have been fabricated by many different foundries with resulting dimensional variations, some may be old and worn while other are new, and a few undoubtedly exist that have been sprung or otherwise bent out of shape. The net result is that the prior art manhole extensions which depend upon relatively close tolerances to produce a water-tight fit will all too often fail to do so. Equally significant is the fact that some of these same ex- 3,294,000 Patented Dec. 27, 1966 tensions will not even fit into an undersize or mishapen ring.

The other factor worthy of specific mention is the ease of insertion and removal. Quite a number of the presently-used devices for this purpose are difficult to insert, complicated to operate and thus expensive from both the initial cost and labor standpoints. It goes without saying that the talents of the skilled labor employed by the various public utilities who make use of these underground facilities are better used in making the necessary repairs than straining to insert a manhole extension.

These and other problems have been in large measure eliminated by the manhole extension that forms the subject matter of the present invention. The sealing difficulties are overcome by confining an inflatable gasket in an outwardly-facing channel-shaped annulus sized slightly smaller than the opposed portion of the ring against which the water-tight seal is to be made. By making the gasket seat undersized, the extension can accommodate all but the most gross irregularities in the ring and the inflatable gasket can, of course, expand or otherwise deform to accommodate such abnormalities as exist in the surface it seals against. Even debris found on the shoulder of the manhole ring will seldom injure the gasket or cause same to fail to produce the desired water-tight seal.

Furthermore, the extension herein disclosed is reversible and will accommodate either of the two basically different sizes of manhole rings in common use today. The gasket, being elastic, can be stretched the inch or two necessary to accommodate the larger of the manhole openings or, if preferred, two different gasket sizes can be used.

It is, therefore, the principal object of the present invention to provide a novel and improved manhole riser or extension.

A second objective is the provision of a device of the type aforementioned that utilizes a novel inflatable gasket which accommodates even gross irregularities in the mating surface against which it is to seal.

Another object of the invention is to provide a manhole riser that is reversible so that it can be used with either of the two common manhole sizes.

Still another objective of the invention herein claimed is to provide a simple one-piece extension for manholes that requires no complete gadgetry for varying the diameter thereof, the latter being taken care of by the inflatable gasket.

An additional object of the invention is the provision of a manhole extender that eliminates the need for close manufacturing tolerances in either the extender or the manhole ring it joins to produce the water-tight seal.

Further objects are the provision of a device for preventing the entry of water into an underground installation that is simple, inexpensive, versatile, easy to install, rugged, foolproof, lightweight and compact.

Other objects will be in part apparent and in part pointed out specifically hereinafter in connection with the description of the drawings that follows, and in which:

FIGURE 1 is a bottom plan view of the manhole extender or shield of the present invention, portions thereof having been broken away and shown in section to reveal the gasket; and,

FIGURE 2 is a vertical diametrical section showing the unit in place within a manhole in water-tight sealed engagement with the ring bordering same.

Referring now to the drawings for a detailed description of the invention and, initially, to FIGURE 2 for this purpose, it will be seen that reference numeral 10 has been employed to identify the manhole extension assembly in a general way and that the latter assembly attaches in sealed relation to a unit which will henceforth be referred to as a manhole ring 12 that is mounted in the ground, street, sidewalk or other similar supporting surface designated by reference numeral 14. Manhole ring 12 is of conventional construction and includes an annular shoulder 16 recessed beneath the upper edge -18 thereof that lies in flush relation to the surrounding pavement 14 or the like. Bordering shoulder 16 is a cylindrical section of increased diameter 20 that cooperates with said shoulder to define a ledge upon which a lid or cover (not shown) can be supported in recessed relation. Ordinarily the manhole ring 12 forms the uppermost extremity of a vertical standpipe that defines and shores up the passage 22 through which access is had to a subsurface installation of some nature.

With reference now to both figures of the drawing, it will be seen that the extension assembly comprises two elements, namely, a tubular extension 24 and an inflatable gasket 26. The tubular extension 24, in the particular form shown, is substantially cylindrical and of a major diameter (X) approximately the same as the interior dimension of the larger of the two manhole rings it is to be used with, only the smaller ring having been illustrated. In other words, when used with the small manhole ring 12 of FIGURE 2, the portion 28 of the extension that projects above ground level is larger in diameter (X) than by interior ring diameter (Y).

Formed integrally along the bottom edge of the tubular section 28 is an outwardly-opening continuous annular channel 30 defined by upper and lower inwardly-extending radial flanges 32 and 34 joined together along their inner margins by a narrow cylindrical wall 36 of approximately the same diameter as the inside diameter (Y) of the smaller manhole ring 12. As shown, the upper inwardly-extending radial flange 32 is slightly wider than the bottom one 34, the latter being sized to slip easily into the annular recess in the top of the smaller ring 12 past cylindrical enlargement 20 and thus accommodate any irregularities in the latter surface. The narrower inwardly-extending bottom flange is, therefore, adapted to rest on ring shoulder 16 as shown in FIGURE 2 although this is not absolutely necessary as will be explained presently.

Upper inwardly extending radial flange 32, on the other hand, projects slightly beyond the upper edge 18 of the small ring and could, if desired, rest on the latter and support the extension assembly in place of the narrow flange, it being immaterial which of these flanges, or both, provide the surface that rests upon the ring. The particular flange that functions as outlined above is, of course, a function of the height of cylindrical wall 26 in relation to the height of corresponding enlarged cylindrical section 30 of the ring 12.

The real significance of flanges 32 and 34 together with wall 36 is that they cooperate to define annular channel 30 which, in turn, cooperates with section 20 of the ring to produce a continuous annular closed cavity adapted to confine the inflatable gasket 26. Channel 30 holds this gasket in place in deflated condition while the tubular extension is inserted into the top of the ring and rests either on top thereof or on its shoulder 16. Cylindrical wall 36 contains an aperture 38 adapted to pass the inflation valve 40 of the gasket. Once in place as shown, a simple hand pump or even lung pressure is all that is necessary to inflate the gasket until it lies in continuous annular water-tight sealed contact with the top, bottom and sides of the passage formed by the channel and ring surface 20. The above operation can, of course, be performed in the matter of a minute or two by unskilled persons without damageto the gasket or other structures. The resulting extension will prevent ground water from flowing into the passage 22 as long as it does not become deep enough to overflow the top edge of the extension. It has been found that an ordinary bicycle inner tube provides an excellent but inexpensive, gasket. Of major significance is the fact that the above-described assembly is purposely made somewhat undersize, yet, the gasket, being inflatable, fills up any gaps resulting from this undersized condition and also conforms to any irregularities in size and shape of the ring.

The only other structure that requires detailed description are the upper and lower outwardly-extending radial flanges 42 and 44 that encircle the upper portion of tube 28. Upper outwardly-extending flange 42 is located at the extreme top edge of tubular section 28 and performs the exact same function as flange 34 when the assembly 10 is inverted and placed in a large diameter ring. Likewise, flange 44 which is somewhat wider than flange 42 and lies in spaced parallel relation therebeneath, performs the self-same function as flange 32 with the extension assembly inverted and positioned in the larger ring. The portion 46 of tubular section 28 that lies between flanges 42 and 44 contains an aperture 48 for the inflation valve 40 of the gasket.

As aforementioned, gasket 26 is elastic and can be stretched to fit into the larger of the outwardly-opening channels 50 defined between flanges 42 and 44, however, the better practice is probably to provide a second gasket (not shown) that is larger in diameter and of a correct size to fit into the large ring channel.

Finally, it is significant to note that with the extension in position of FIGURE 2, the inside diameter of tubular section 28 is approximately the same as the cylindrical section of increased diameter 20 that borders the shoulder of the manhole. Thus, two or more extensions can be stacked one on top of the other, as shown in FIGURES 3 and 4 so that the inflatable seal 26 engages and seals against that portion of tubular section 28 that lies between flanges 42 and 44. It will be obvious that inwardly extending flange 32 will rest atop outwardly extending radial flange 42 when the shields are stacked. This method of using the shields protects against flood conditions Where the height of a single ring becomes inadequate. Stacking the extensions 10 can also be accomplished with larger diameter manholes by merely inverting the extensions and engaging the manhole ring by the larger diameter channel 50 as illustrated in FIG- URE 4. In this configuration, the outward flange 42 of the second extension rests upon the inward flange 32 of the first extension. When used in this manner, there would be two inflatable gaskets 26 in the first extension 10; one in channel 50 and the other in channel 30.

Having thus described the several and novel features of the manhole extension of the present invention it will be apparent that the many Worthwhile objectives for which it was developed have been achieved. Although but a single specific embodiment of my invention has been illustrated and described herein, I realize that certain changes and modifications may well occur to those skilled in the art within the broad teaching hereof; hence it is my intention that the scope of protection afforded hereby shall be limited only insofar as said limiltations are expressly set forth in the appended claims.

What is claimed is:

1. An above-ground detachable extension for manholeholes and the like of a type bordered by a ring having an annular lid-supporting shoulder recessed into the top thereof which comprises: an upstanding tubular member sized to define a continuation of the manhole bordering ring, means carried by the tubular element located adjacent to both ends thereof to produce a continuous annular channel sized for insertion into the recess formed above the lid-supporting shoulder of the manhole ring, said channel-producing means cooperating with that portion of the manhole ring lying above the lid-supporting shoulder to define a substantially enclosed continuous annular gasket cavity, the channel producing means includes a pair of radial spaced apart flanges located at each end of said tubular element, cylindrical wall sections bridging the spaces between each pair of flanges in integral relation, the cylindrical wall section of the first pair of flanges comprises a portion of the tubular element with one of said flanges bordering the edge of the tubular element and narrower than the remaining flange, the cylindrical wall section connecting the second pair of radial flanges is of lesser diameter than said tubular element, one of said second radial flanges forms the connection between said tubular element and cylindrical wall section, a pair of continuous annular tubular elastic inflatable gaskets sized to fit within each of said channel means in encircling relation with the tubular element.

2. The detachable extension for manholes as set forth in claim 1 which further includes: means accessible from inside the tubular element connected into the interior of each gasket for inflating same to the extent it expands into continuous annular water-tight sealed relation with portions of the ring and channel means that form the cavity thereof and enclose same.

3. The detachable extension for manholes as set forth in claim 1 in which: the other flange of said second pair having an outside diameter less than the inside diameter of said tubular element.

References Cited by the Examiner JACOB L.-NACKENOFF, Primary Examiner. 

1. AN ABOVE-GROUND DETACHABLE EXTENSION FOR MANHOLEHOLES AND THE LIKE OF A TYPE BORDERED BY A RING HAVING AN ANNULAR LID-SUPPORTING SHOULDER RECESSED INTO THE TOP THEREOF WHICH COMPRISES: AN UPSTANDING TUBULAR MEMBER SIZED TO DEFINE A CONTINUATION OF THE MANHOLE BORDERING RING, MEANS CARRIED BY THE TUBULAR ELEMENT LOCATED ADJACENT TO BOTH ENDS THEREOF TO PRODUCE A CONTINUOUS ANNULAR CHANNEL SIZED FOR INSERTION INTO THE RECESS FORMED ABOVE THE LID-SUPPORTING SHOULDER OF THE MANHOLE RING, SAID CHANNEL-PRODUCING MEANS COOPERATING WITH THAT PORTION OF THE MANHOLE RING LYING ABOVE THE KID-SUPPORTING SHOULDER TO DEFINE A SUBSTANTIALLY ENCLOSED CONTINUOUS ANNULAR GASKET CAVITY, THE CHANNEL PRODUCING MEANS INCLUDES A PAIR OF RADIAL SPACED APART FLANGES LOCATED AT EACH END OF SAID TUBULAR ELEMENT, CYLINDRICAL WALL SECTIONS BRIDGING THE SPACES BETWEEN EACH PAIR OF FLANGES IN INTEGRAL RELATION, THE CYLINDRICAL WALL SECTION OF THE FIRST PAIR OF FLANGES COMPRISES A PORTION OF THE TUBULAR ELEMENT WITH ONE OF SAID FLANGES BORDERING THE EDGE OF THE TUBULAR ELEMENT AND NARROWER THAN THE REMAINING FLANGE, THE CYLINDRICAL WALL SECTION CONNECTING THE SECOND PAIR OF RADIAL FLANGES IS OF LESSER DIAMETER THAN SAID TUBULAR ELEMENT, ONE OF SAID SECOND RADIAL FLANGES FORMS THE CONNECTION BETWEEN SAID TUBULAR ELEMENT AND CYLINDRICAL WALL SECTION, A PAIR OF CONTINUOUS ANNULAR TUBULAR ELASTIC INFLATABLE GASKETS SIZED TO FIT WITHIN EACH OF SAID CHANNEL MEANS IN ENCIRCLING RELATION WITH THE TUBULAR ELEMENT. 